Process of concentrating sulfite waste liquor.



G. ELLIS.

PROCESS OF CONGENTRATING SULFITE WASTE LIQUOR. APPLIOATlON FILED r213.16, 1912.

1,057,416, Patented Apr. 1, 1913.

6 7 JIM/w .mursr mew max, Q'wfiaw Mei 4 UNITED STATES PATENT @TTT@E.

CARLETON' ELLIS, OF MONTCLAIR, NEW JERSEY, ASSIGNOR TO ELLIS-FOSTER GOM-PANY, A CORPORATION OF NEW JERSEY.

PROCESS OF CONCENTRATING SULFITE WASTE-LIQUOR.

Specification of Letters Patent.

7 Patented Apr. 1,1913.

Application filed February 16,1912. Serial No. 678,153.

To all 'w/w m, it may concern Be it known that I, CARLETON ELLIS, acitizen of the United States, residing at Montclair, in the county ofEssex and State of New Jersey, have invented certain new and usefulImprovements in Processes of Concentrating Sulfite Waste Liquor, ofwhich thefollowing is a specification.

This invention relates. to the concentration or utilization of wastesulfite liquor and to the process of making same and relatesparticularly to a method of concentration whereby hydrolytic changes arebrought about during the concentration which result inthe production ofa concentrated liq uor having many useful properties.

' In themanufacture of concentrated waste sulfite liquor, it hasheretofore been pro posed to neutralize the liquor and concentrate it ina multiple efi'ect vacuum an as for instance the Ekman process, JrermanPatent 81,648, etc. The treatment of sulfite liquor in this mannerresults in its concentration without. any substantial change in itschemical composition and therefore does not succeed in developing to thehighest degree the useful dextrinous properties which are secured bytreatment in the manner hereinafter described.

By the present process, the crude unconcentrated liquor is firstpreferably blown with air, in order to remove any free sulfurous acidwhich acid later may berecovered by passing thesulfurous-acid-containing air into a suitable absorbing chamber. The airused for this purpose may be heated or the liquor itself may be warmedor both the air and liquor may be used in a heated condition. Thesulfurous acid removedmay be converted into lime sulfite' or lime andmagnesium sulfite or bi-sulfite suitable for use again in the pulpdigesters. After the liquor has been freed from a substantialpropo-rtion of free sulfurous acid gas, it is treated with ordinaryquicklime or ordinary dolomite lime or with soda pulp waste lye until itis alkaline. It may then be filtered through a filter bed and conductedinto a vacuum pan which preferably should be a multiple efiectevaporator in order to secure rapid and inexpensive concentration. Herethe liquor is evaporated to a consistency of 25 to 33 Be. and duringthis operation, owing to the alkaline character of the liquor, re-

act-ions occur which produce the dextrinous bodies desired.

As a modification, the lime or other alkali added to produce an alkalinereaction may be introduced into the liquor prior to the air treatment,and by aeration in the presence of an alkaline body, dextrinous changesare set up which may be satisfactorily completed in the evaporators.through the evaporators, the liquor may be run through a filter press inorder to remove certain insoluble products which are formed as theresult of the alkaline hydrolysis, and by such filtration a cleartransparent liquor is produced. This may be rendered neutral or acid asdesired.

A satisfactory method of securing the alkaline solution is that ofneutralization to a large extent with lime and the subsequent additionof soda pulp waste liquor to secure an alkaline reaction. Suitableproportions of lime to caustic soda are 7 :1 up to 10:1. Instead of sodapulp waste liquor carbonate of soda or caustic soda maybe employed.

The accompanying diagrammatic drawings show in elevation the mannerinwhich the process may be carried out.

In the drawings, 1 is a pressure blower supplying air to the aeratingchamber 6 through the pipe 2, preheater 3 and pipe 5. The by-pass isarranged to shunt cold air around the preheater 3, when the "air is usedat ordinary temperatures. The air discharges at the bottom of theaerating chamber 6 and escapes through the pipe 10. The chamber 6 isprovided with a double bottom 7, through which steam is passed by themeans of inlet. 8 and outlet 9. From the aerating chamber, a pipe 12leads to the settling tank 11. This is connected with the filter bed 14by the pipe 13'. A by-pass15 After passing.

permits of cutting out of tank 11 if de-,

sired. From the filter bed, a pipe 16 leads to the evaporator 17, and adischarge ipe 18 leads from the evaporator 17 to the lter press 19.

In carrying out the invention with the apparatus above indicated, thetank 6 is filled with waste sulfite liquor and is preferably heated to atemperature of about i 40. Air at a ten'iperaturc of 60 011809 (l.is'introduced into the tank under pressure exerted by the blower 1. Thefree s lfurous acid is removed with the air which escapes through theexit pipe, 10. Lime may then be added to make an alkaline solution andthe liquor further treated with heated air allowing the temperature ofthe liquor to gradually rise until it reaches about 60 C. At this point,the liquor may be run into .the filtering chamber 11 and then throughthe filter .bed 14. The clear liquid from the filter bed 1 L passes intothe multiple effect evaporator 17 and there reduced to a gravity of from25 to 33 B. or thereabout, at the same time, being hydrolyzed andpartially converted into dextrinous bodies, or bodies of that character,with the formation of a small amount ofinsoluble material. If hydrolysisis not carried on in the tank 6 by the addition of lime to alkalinitywith subsequent air treatment, the treatment in the settling tank 11 maybe omitted and the liquor may be sent direct to the filter bed 14 by theshunt 15. The liquor passed in this manner has many uses. For example,it may be employed as a briquetin material or binder in the manufactureof fuel briquets and as a binder for similar bonding operations. It maybe used as a paper size and especially as a size and mordant inconjunction with gelatin or glue. It may be salted out from itsconcentrated solu-- tion as a precipitate which may be dried and used asa dextrin substitute. The drying may be carried out by means of heatedair in admixture with the atomized concentrated liquor. The liquor maybe acidified and tanning compositions produced therefrom, or if desired,rendered entirely neutral and used as an addition to tanning extracts.For tanning purposes, the liquor is of a more useful character than thatproduced by evaporation of a neutral liquor as the hydrolytic changesset up in the composition during its treatment in alkaline solution,result in the elimination of certain of the semiresinous bodies whichare detrimental to leather. Emulsions may be made from it with mineraloils such as kerosene oil and the like producing useful insecticides.Emulsions mayalso bemade from tar acids and coal tar and the like. Someof these'emulsions are particularly useful in the laying of road dust.The liquor of itself dries to a rather brittle product which is notespecially well adapted to be used alone as a road dust layer, but inconjuncti n with a small amount of calcium chlorid or magnesium chlorid,a desirable dust layer and road binder is secured.

The formaldehyde addition roducts have some uses as a disinfectant an inconnection with the sizing and waterproofing of paper with glue. The taracid compositions may be used as sheep dips as the sulfite liquor in thepresent form is a useful substitute for the rosin soap ordinarilyemployed. A neutral liquor may be used as an addition to prepared foodsintended for horses and cattle and acts as a binder and nutrientmaterial. For this purpose, I prefer to push the hydrolysis as far aspossible in order to make the composition readily assimilable.

Having described my invention to the details of which I do not wish tobe limited, what I claim is:-

1. The process of treating waste sulfite liquor which comprises blowingwith air to remove a portion of the free sulfurous acid, neutralizing toalkaline reaction and concentrating under diminished atmosphericpressure and in freeing said liquor from insoluble products ofhydrolysis.

2. The process of treating waste sulfite liquor comprising aerating withair to remove a substantial proportion of the free sulfurous acid,adding an alkali to produce an alkaline reaction, filtering andconcentrating under diminished atmospheric pressure and in freeing saidliquor from insolui ble products of hydrolysis.

3. The process of treating waste sulfite liquor comprising blowing wlthalr to remove free sulfurous acid, rendering alka "line,

further aerating and heating the composition to develop hydrolyticchanges, and concentrating under diminished atmospheric pressure and infreeing said liquor from insoluble products of hydrolysis.

4. The process of treating waste sulfite liquor comprising blowing withheated air .to remove free sulfurous acid, rendering slightly alkalineand concentrating under diminished atmospheric pressure, wherebyproduct-s of hydrolysis are produced and in freeing said liquor frominsoluble products of hydrolysis.

5. The process of treating waste sulfite liquor comprising heating saidliquor to a temperature of about 40, aerating with air at a temperatureof 60, rendering alkaline with lime, and heating the liquor to about 60with continued aeration, whereby hydrolytic changes are developed, infiltering the liquor and concentrating under dimin-' ished atmosphericpressure andin freeing said liquor from insoluble products ofhydrolysis. I

In testimony whereof I have aflixed my signature in presence of twowitnesses.

CARLETON ELLIS.

FRANCES I. NEWMAN.

